A variety of radar techniques have been proposed as a technique to obtain information about internal structure of an observation object by irradiating the object with an electromagnetic wave and receiving its reflected wave etc (for example, see Patent Document 1). This type of traditional radar device can, for instance, detect the electromagnetic wave reflected at a boundary part within the observation object where a medium changes, and obtain information about the structure inside the observation object (for example, objects etc present in the observation object) based on its detection result.